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UnomiApplication · Apache

CVE-2020-13942

CRITICAL · 9.8 CVSS v3.1 Published 2020-11-24
Fix available
A fix is available. Upgrade to 1.5.2 or later.
See remediation →
100/100
Remediation priority · Urgent
High EPSS Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
It is possible to inject malicious OGNL or MVEL scripts into the /context.json public endpoint. This was partially fixed in 1.5.1 but a new attack vector was found. In Apache Unomi version 1.5.2 scripts are now completely filtered from the input. It is highly recommended to upgrade to the latest available version of the 1.5.x release to fix this problem.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-20

The application accepts input without confirming it is well-formed or within expected bounds, so malformed data can push the program into states its author never anticipated. Attackers probe these gaps to trigger crashes, bypass logic, or feed tainted values into more dangerous operations downstream. Remediating it well means validating and normalising every input at the boundary against a strict allow-list — not merely filtering known-bad values.

General guidance for the improper input validation class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
UnomiApplication
Affected:>= 1.5.0, < 1.5.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.5.2 or later
Fixed in 1.5.2
Recommended fix High confidence

Apache Unomi 1.5.2 (or latest 1.5.x release)

  1. Stop the running Apache Unomi instance
  2. Download Apache Unomi version 1.5.2 or the latest 1.5.x release from the official Apache Unomi distribution (https://unomi.apache.org/download.html)
  3. Backup the existing Unomi installation directory and any custom configurations
  4. Extract the new version to replace the existing installation
  5. Restore any custom configuration files (such as etc/custom.system.properties, etc/jetty.xml, etc/org.apache.unomi.cfg file) from the backup
  6. Start the Apache Unomi service
  7. Verify the fix by confirming the /context.json endpoint no longer accepts injected OGNL or MVEL scripts
Caveat Review release notes for any configuration or API changes between your current version and 1.5.x; minor version upgrades within 1.5.x typically have minimal breaking changes

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,300. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-13942 in production — separate from our analysis above.

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